The use of fragrances as perfumes and odorants has existed for as long as can be remembered. These substances were early obtained from suitable animal and plant sources, and since the nineteenth century synthetic fragrances have been prepared by chemists.
The requirements for a desirable fragrance are subjective and change with the fashion. This gives rise to a constant demand for new fragrances which may stand alone or act as compliments to those already available.
The problem faced by the synthetic chemist is the lack of predictability of success in producing an acceptable fragrance since it has yet to be established that there is any predictable relationship between chemical structure and fragrance characteristics or nuances.
U.S. Pat. No. 4,302,363 describes an isomer mixture of 4(5)-acetyl-7,7,9(7,9,9)-Trimethyl bicyclo[4.3.0]non-1-ene which is a valuable fragrance which has a warm ambergris odor.